Digital versatile discs (DVD) or Blu-ray (a registered trademark) discs (BDs) are widely used as an information recording medium for recording a variety of content such as movies or music.
Data such as audios and subtitles is recorded in a BD-ROM which is a medium having content such as movies recorded therein in advance together with, for example, a high definition (HD) image which is a high quality image.
HD images, so-called high-definition-compatible 2K images, are usually recorded in most of current BD-ROMs, but as the image quality is improved, mediums having an ultra high definition (UHD) image recorded therein are expected to increase in the future.
Further, high resolution images such as 4K images or 8K images are representative examples of the ultra high definition image (UHD image), but the ultra high definition image is not limited to the high resolution image, and wide dynamic: range images, images having a wide output color space, and the like are also called the UHD images.
In the future, mediums having a UHD image recorded therein are expected to increase.
For example, the ultra high definition images (UHD images) such as 4K images are larger in a processed data amount per unit time than 2K images which are the HD images. As a result, it is necessary to increase a data recording density or a data reading rate for discs such as BDs as well.
A data recording form of the ultra high definition image (UHD image) for the BD is currently being standardized in Blu-ray (a registered trademark) Disc Association (BDA) which is a standardization organization.
For a BD-DHD-ROM disc which is a BD-ROM disc having UHD content including a UHD image recorded therein, standards of various types of discs such as a multi-layer type disc having two or more recording layers in addition to a single layer type disc having a single data recording layer are under discussion.
The BD-UHD-ROM has a unique physical format different from those of the existing BD-ROMs. For example, the BD-UHD-ROM is a disc having a unique physical format in which a data recording capacity per disc layer and a reading bit rate are different from those of existing BD-ROM discs.
Further, a logical format in which a type, an arrangement, and the like of data files recorded in the BD-UHD-ROM disc is also a unique logical format different from those of the existing BD-ROMs.
In a case where the BD-UHD-ROM disc having content such as movies recorded therein is manufactured, it is necessary to perform a reproduction test of whether or not content recorded in the disc is normally reproduced.
After normal reproduction is confirmed in the reproduction test, mass production of the ROM disc is performed.
However, for example, in order to manufacture the BD-UHD-ROM disc having a certain UHD content recorded therein, it is necessary to manufacture a mold and stamper specific to content, and thus there is a problem in that it takes a time and cost.
In this regard, the UHD content scheduled to be recorded in the BD-UHD-ROM disc is written in a BD-R disc, a BD-RE disc, or the like which is a data rewritable disc, and a reproduction test of whether or not the UHD content is reproduced normally using the data rewritable discs is performed. Accordingly, the cost and time required for the reproduction test can be significantly reduced.
It is because if the BD-R disc or the BD-RE disc which is a data rewritable disc is used, even in a case where a reproduction error occurs, it is possible to rewrite modified content in the BD-R disc or the BD-RE disc and perform the reproduction test for the modified content.
However, as described above, the BD-DHD-ROM disc has the unique physical format and the unique logical format.
In a case where data of the unique format is recorded in the current BD-R/BD-RE disc, there is no guarantee that reproduction of UHD content from the BD-R/BD-RE disc is performed normally.
In other words, in a case where the UHD content to be recorded in the BD-UHD-ROM disc is copied and recorded in the BD-R disc or the BD-RE disc, a reproducing device performs a reproduction process according to the physical format and the logical format of the BD-R disc or the BD-RE disc.
However, the reproduction process is a process different from the reproduction process according to the physical format and the logical format compatible with the BD-DHD-ROM disc, and thus the content is not normally reproduced.
For example, a data reading bit rate specified as the logical format compatible with the BD-UHD-ROM disc is different from the reading bit rate specified as the logical format compatible with the BD-R disc or the BD-RE disc.
Even when the reproducing device reads and reproduces the UHD content recorded in the discs at the reading bit rate compatible with the BD-R disc or the BD-RE disc, the normal reproduction is unable to be performed.
In order to normally reproduce the BD-UHD-ROM record content, it is necessary to perform reproduction according to the reading bit rate corresponding to the BD-UHD-ROM record content.
However, there is a problem in that, at the present time, there is no provision for a process of reading or reproducing the UHD content from the BD-R disc or the BD-RE disc, and the normal reproduction of the UHD content from the BD-R disc or the BD-RE disc is unable to be executed.
Further, a related art in which a reading rate and a reproduction process from a disc are described is disclosed in, for example, Patent Document 1 (JP 2010-250939A).